【正文】 prevention measure. crack and prevention Temperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete pare the earth area of the concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350550 kg/m 3, each sign square the rice concrete will release a calories of 1750027500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃ or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should pull should dint exceed the anti of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation. The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave。s anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack. The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open this kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on of prevention measure:While being to choose to anticipate with the alkali activity small freestone is the in addition which choose to use low lye mire with low alkali or have no is the Chan which choose to use acmodation with anticipate to repress an alkali bone to anticipate reaction. Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar of prevent measure from have:One is assurance reinforcing bar protection the thickness of the is a concrete class to go together with to want is a concrete to sprinkle to note and flap Dao airtight is a reinforcing bar surface layer Tu2 Shua antisepsis coating.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》。Thorough with pierce through sex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segment appear, in the center more width the size be different, be subjected to temperature variety influence more obvious, winter pare breadth, summer more concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too emergence of the this kind crack will cause the rust eclipse of reinforcing bar, the carbonization of concrete, t